Method of continuously casting strip metal



Sept. 18, 1956 J. B. BRENNAN 2,763,044

METHOD oF CONTINUoUsLY CASTING STRIP METAL Filed June 4. 1949 2 Sheets-Sheet 1 JOJEPH BEEN/VAN MQWM Sept. 18, 1956 J. B. BRENNAN METHOD OF CONTINUOUSLYv CASTING STRIP METL.

2 sheets-sheet 2 Filed June 4, 1949 INVENTOR. JOSEPH B. ,BEEN/VAN METHOD F coNrnsUosLY cAsTmG STRIP METAL Joseph B. lrennan, Bratenahl, Ohio Application time 4, 1949seria1Na. 97,195 1 Claim. (Cl. 22200.1)

This invention relates to continuous pressure casting of a head of molten metal through an orifice or conduit against the face of a moving heated band of dissimilar metal under constant pressure control and constant temperature control so that a lamination of two orlmore metal strips or shapes is produced by passing the joined cast and moving band of bimetal through a die defining the contour and cross-sectional dimensions of the finished strip.

According to my U. S. application Serial No. 642,968, filed January 23, 1946, now abandoned, I disclose the casting of molten metal preferably under pressure against a continuously advanced strip of another metal while said strip is confined in a die.

Such apparatus is illustrated in Figs.v 9-12 of the drawings submitted with said application Serial No. 642,- 968, and this application relates to further improvements over said application Serial No. 642,968, and thus is a continuation-in-part of the said application.

According to this invention I am able to continuously bond a cast molten metal such as a leaded bronze to a heated and continuously advanced strip of cold rolled steel which can be used for making split bearings.

A feature of this invention is a synchronized means of advancing and withdrawing a strip of steel for example through a die wherein for example the molten bronze is applied thereto in such a manner that no serious strain is applied to the steel strip during the application of the molten metal thereto.

Another feature of this invention is a temperature control means throughout the passage of the to-be-bonded metal strip through the die and during the application of the molten metal layer thereto.

Another feature of this invention is the atmospheric pre-cleaning and control of the to-be-bonded strip prior to the entrance into the lamination die.

Y Another feature of this invention is the constant rate of feed and withdrawal mechanism for the feeding of molten metal to the lamination die.

Another feature of the invention is the provision of apparatus which may be used to feed molten metal at a constant rate and constant temperature and pressure onto a to-be-bonded strip of temperature controlled heated metal in such a way that a good bond is assured.

The apparatus of this invention may be used at atmospheric pressures or at superatmos'pheric or subatmospheric pressures such as in conjunction with apparatus disclosed in my pending application Serial No. 25,756, iiled May 7, 1948, now Patent No. 2,569,150, dated September 25, 1951.

Other objects and advantages will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, said invention, then, comprises the features hereinafter fully described and particularly pointed out in the claim, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however,

States Patent ice of but afew of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

Fig. l is a vertical cross-sectional view of one embodiment of this invention;

Fig. 2 is a vertical cross-sectional view of another embodiment of this invention;

Fig. 3 is a fragmentary cross-sectional view of the roll in Fig. 2; and

Fig. 4 is a cross-sectional view taken substantially along the line 4 4, Fig. 1.

Referring to the drawings which accompany this specication, the numeral 1 in Fig. l represents a tiltabl feeding crucible for feeding molten metal to the crucible 2 so as to preferably maintain a constant head of metal 3 therein which is done by means of the overflow 12 which overilows'into the receptacle 4. Y

The crucible 2 and its contents 3, Fig. 1, are preferably heated by high frequency coils 7 to a constant temperature and feeds a lstream of molten metal '8 therefrom through opening 13 to slit ended die 14 which slit ended die is constant temperature controlled preferably by means of the high frequency coils 7a at a Zone adjacent the entrance feed of the molten metal 8 into the slit ended die 14. n j

The metal 5 to be bonded is fed in ilat strip form 6 through a reducing cleaning gas flame supplied by jets 15 to the surfaces thereof and into the slit and of the die 16 by means of a belt y9 backed up by a joined series' of permanent or coil magnets 9A advanced therewith as a supporting belt. Y i

The magnetic belt 9 may be a single continuous belt having magnets attached to the inside face thereof as best shown in Fig. 4 and moving therewith' to feed the strip 6 of, for example, Viiat precleaned steel into the feed-in slit of die blo'clt 16 and all along underneath said steel strip 6 until it emerges after being coatedwith a surface of, for example, leaded bronze at the exit slit 11 of die block 17. The magnets 9A may be recessed to receive rollers 9B for engaging support' 9C to thereby facilitate the movement of the joined series of magnets 9AA longitudinally along the support 9C. p

Under `such conditions the magnetic belt 9 holds the strip steel 6 firmly and feeds it through the molten metal application zone indie 14 while the Vsteel is heated on at least its exposed face to 1950 F.-2000`F. even though the heated section of strip 6, Fig. 1, has teniporarily lost its magnetic character due to heat while in the molten metal *zone of die 14. At that temperature the vsteel is nearly white hot and plastic, thatis, in a softened condition, and easily distorted if subjected to non-synchronousfeeding and withdrawing forces. v

The drawing herewith shows the magnetic feed and withdrawal belt 9 as in left-hand and right-hand sections both driven by chain- 10 as a preferred construction. y

A. large hollow magnetic roll could be used instead of the belt 9 to advance the strip 6 in and out of the metal application die 14, Fig.` 1, if preferred.

Feed magnetic rolls synchronized at both ends of the slotted die could also be used to feed and withdraw the steel strip 6 through the molten inetal application die 14 if preferred.

According to my invention the steel strip and the molten`metal being applied thereto and the bimetallic strip resulting from such application are enclosed on the top,` bottom and sides by means of the die 14, as well as die shoe 16 and belt 9 and die shoe 17 and belt 9 so that when the bim'etallic strip is withdrawn it is chilled to hold its shape which is substantially the cross-section of the right-hand slot of die 14.

Die shoe 17 ,has a slot therein equal to cross-section of slot at right-hand exit or withdrawal end of die 14 and 3 in conjunction with upper surface of right-hand belt 9 completely encloses the bimetallic strip 11 until it emerges.

Cooling coils 18 gradually cool the produced bimetallic strip 11 as it progresses and also restore the magnetic character to the steel stripjas it is cooled.

The belt surface 9 may be grooved to a depth equal to or greater thanthe thickness and width of the resultant strip 11 or the die shoes 16 and the die14 and the die shoe 177 are preferably' grooved, as illustrated in Fig. 4 for example, in which case the upper surface Vof belts 9 may be smooth.

In any case the belts 9 function so as to snugly hold the advancing strip 6 in-placeiagainst the dieshoe 16 and the die 14 and the withdrawing strip 11 is held against the die 14 and the die shoe-17 snugly;

The upper andlower parts of theV die 14 are in fixed relation when metal is being laminated but may be made adjustable as to width and thickness to suit desired strip dimensions of the finished product.

The coil of steel may be enclosedv in a deoxidizing atmosphere if preferred and may also be placed in a pressure chamber with all the apparatus shown in Fig.'1 if desired except the exit end of the die where the strip 11 emerges. Y Such a pressure chamber as is suitable is'shown in mysaid Patent No. 2,569,150.

The die 14 plus its extension made up of die shoe 16 and the left-hand belt 9 and the die shoe 17 yand the right-.hand belt 9 define a groove just to fit the strip steel 6 as it feeds in then to'accommodate the molten metal and heat zone 14 then to define the cooling zone for strip 11as and after it is shaped and cooled.

The base 19 may be made in sections and the die 14 maybe removable and is preferably so.

Separate electric sources may be used to control heat coils 7, 7a, and heat coil 20.

Heat coil 20 can be a high frequency surface preheater applied to only one side of strip 6 so that only the top side of the strip is heated to plasticity as it passes thereunder as is disclosed in my said Patent No. 2,569,150.

Cooling coils 18 may be separate, part situatein the discharge zone of die 14 and part situate in die shoe' 17, Fig. l.

These cooling coils 18 insure that the strip 11 emerges solid and also that the steel part ofthe strip 11 is magnetic as it emerges and prior thereto.

Thehigh frequency coils may be packed in an insulation where used with a conductive die or die shoe such as graphite.

Fig. 2 illustrates apparatus similar to that described in my Patent No. 2,569,150 as well as certain features for laminating metals disclosed in my application Serial No.V 642,968, filed January 23, 1946. Y

The numeral 31 in Fig. 2 represents sectionally a pressure dome as of metal locked over a base 32.

, Inside the domeV 31 and the base 32 is a cruclble 33 surrounded by a high frequency induction coil 34 for heating the metal 35 and maintaining the same molten.

A gas pressure feed line 36 enters the dome 30 to supply pressure thereto and a graphite die 37 extends as a molten metal conduit from the bottom of the Crucible 33 which conduit or die in turn is heated by high frequency coil 38 and is cooled by uid chamber 39 surrounding the same.

The die 37 terminates over a rotatable hollow wheel 40 as of graphite and a high frequency coil 41 is adjacent the exit of die 2. A high frequency coil 42, Fig. 3, is situate near said termination of said die over said wheeland inside said wheel so as to heat the zone of molten metal application as well as the traveling steel strip 43 fed lfrom roll 44 through slot 45 in carbon shoe` 46. Said shoe 46 is recessed and spaced from outer surface of wheel 40 suciently to form a groove for pas- Sage snugly therethrough of steell strip 43 to-the egress 4 of die 37 so that as and when the molten metal emerges from die 37 the strip steel `43 is heated to about 2000 F., that is, a plastic condition, due to high frequency coils 41 and 42. Thus, the molten metal penetrates one side of the strip steel pores and is formed into a uniform layer onto the exposed upper face of the strip steel, the thickness of said layer being regulated by the spacing of the steel band 4 3 passing by the right-hand side of the feed die 37. The coated steel strip advances over the outer surface of the roll 49 into a cooling zone which has a grooved die shoe 47 heated by high frequency coil 48 and cooled by coolant circulation tubes 49 to regulate the temperature 'of theadvancing bimetallic strip and to solidify same.

Added sprays for coolant are supplied after the bimetal emerges.

The hollow roll 40 may be grooved and/ or flanged as is described in my application Serial No.' 642,968 and the preferred form for die 37 is described in said application. i T

Thefroll 40 may be magnetic to assist in advancing the steel strip without distortion thereof at 2000* F. it being, solid at its entrance and exit.

The rolls 50 may be used to drive hollow roll 40.

The steel coil 44 may be enclosed in a chamber 51 held at a desired pressure and having an atmosphere and temperature such as will assist in the process depend ing on the metals being used.

Fig. 3 is a fragment of roll 40 and bearing thereof having high frequency coil 42 therein.

This roll 40 may be made of anodized aluminum or carbon or graphite or quartz or metal or ceramic material and should be temperature controlled.

The temperature of the zone of metal application mus be above the temperature of the melting point oflthe molten metal being applied to the advancing Vstrip metal, and as aforesaid, the latter is heated to plastic condition, viz. about 2000 F. in the case of strip steel.

The heating of the metal strip and the die at the point of application of the molten metal thereto is-an essential feature of this invention.

Solid metal strips may be cast by the same apparatus continuously by blocking theslit entrances 45 and the groove in the die shoe 46.

Having described my invention what I claim is:

A metal casting process for continuously producing bimetallic strip, comprising the steps of continuously and uniformly moving an elongated rolled strip of metal with one side of successive portions of its length supported on and driven by a synchronously moving, ceramic supporting surface whereby the thus supported strip is in substantially unstressed condition, passing said strip, while thus supported, through a high frequency heating eld which is substantially ineective to heat such supporting surface and which is effective to heat the opposite, exposed side only of said strip to' a temperature rendering said exposed side plastic and exceeding the melting point of a lower melting point metal to be cast thereagainst, casting such molten metal to the heated, exposed side of the supported portion of saidvstrip as the latter passes through such high frequency heating field, said molten metal being heated and maintained in molten condition at its junction with the strip and thereadjacent, moving` the supported portion of said strip and the heated molten metal thereon through such heating field and through a die having a surface laterally spaced from the exposed side of said strip and contacting the exposed side of the molten metal to thus hot-form the cast metal, while heated to molten condition by said heating field and while in longitudinally sliding contact with said die surface, and extracting heat from the supported portion of said strip and the hot-formed applied metal thereon as it moves beyond such heating eld and while Within said die to solidify the applied metal thereon'and therebyL produce' a bimetallic strip in' which the 'applied molten' metal component is of thickness as determined by the spacing of the die surface from the exposed side of the supported portion of said strip.

References Cited in the le of this patent 5 UNITED STATES PATENTS 672,663 Baxter et a1. Apr. 23, 1901 727,291 Clark May 5, 1903 1,531,472 Baker Mar. 31, 1925 10 1,600,668 Hazelett Sept. 21, 1926 1,906,400 Moon May 2, 1933 1,943,351 Stocketh et al. Ian. 16, 1934 1,948,505 Bray Feb. 27, 1934 1,956,467 Palm Apr. 24, 1934 15 1,995,258 Stocketh Mar. 19, 1935 6 Palm Sept. 24, 1935 Salzman Feb. 25, 1936 Hudson Sept. 6, 1938 Hudson Sept. 6, 1938 Hudson Sept. 6, 1938 Edwards June 11, 1940 Ness Apr. 29, 1941 Merle Nov. 10, 1942 Merle May 2, 1944 Hensel et al. Jan. 6, 1948 Reynolds Mar. 6, 1951 FOREIGN PATENTS Great Britain Sept. 1, 1939 Great Britain Sept. 29 1939 Germany Sept. 26, 1941 

